1. Field of the Invention
The present invention relates to fan wheel structures, and more particularly to fan wheel structures having axial blades and blower blades.
2. Description of the Related Art
A wide variety of fan wheels for miniature heat dissipating fans have heretofore been provided. Conventional fan wheels include two types: axial type and blower type. An axial type fan wheel includes axial blades each extended in a direction that has an angle with an axial direction for driving air along the axial direction. A blower type fan wheel includes blower blades each extended in a direction parallel to the axial direction for driving air in a plane perpendicular to the axial direction. When using a miniature heat dissipating fan with axial blades for cooling a circuit board or the like, cool air is accumulated on the surface of the circuit board and then forced to expand outward along a plane perpendicular to the axial direction. In this case, hot air as a result of absorbing heat generated by the circuit board will move upwardly and thus causes an obstruct to the outward expansion of the cool air. As a result, the heat dissipating function is adversely affected. When using a miniature heat dissipating fan with blower blades for cooling a circuit board or the like, cool air is driven along the plane perpendicular to the axial direction. In this case, hot air as a result of absorbing heat generated by the circuit board that moves upwardly is also driven along the plane perpendicular to the axial direction. The upwardly moving hot air encounters and thus adversely affects the cooling effect of cool air that moves downwardly to the surface of the circuit board.
The present invention is intended to provide improved fan wheels for miniature heat dissipating fans to solve the above problems.